lib: consolidate util macros in util/util.h

This change groups the offsetof, container_of and ARRAY_SIZE macros in a
single header file util/util.h.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

1 files changed, 34 insertions, 0 deletions

diff --git a/lib/util/util.h b/lib/util/util.h
new file mode 100644
index 0000000..30b472d
--- /dev/null
+++ b/lib/util/util.h
@@ -0,0 +1,34 @@
+/*
+ *  Copyright (C) 2013 IBM Corporation
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef UTIL_H
+#define UTIL_H
+
+#ifndef container_of
+#define container_of(_ptr, _type, _member) ({ \
+	const typeof( ((_type *)0)->_member ) *__mptr = (_ptr); \
+	(_type *)( (char *)__mptr - offsetof(_type,_member) );})
+#endif
+
+#ifndef offsetof
+#define offsetof(_type, _member) ((size_t) &((_type *)0)->_member)
+#endif
+
+#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
+
+#endif /* UTIL_H */
+